1. Field of the Invention
The present invention relates generally to a transmission device applied to rotary shafts, and more particularly to a transmission device including at least one rotary shaft, a drive member movable along with the rotation of the rotary shaft, a driver, a turning unit and a transmission unit. When the transmission unit is longitudinally moved, a carrier body is driven by the transmission unit to lift or lower a base body in accordance with the operation mode of an electronic apparatus.
2. Description of the Related Art
There are various electronic apparatuses provided with covers or display screens, such as mobile phones, notebooks, PDA, and electronic books. The covers or display screens are pivotally mounted on the electronic apparatuses via pivot pins or rotary shafts, whereby the covers or display screens can be freely rotated and opened/closed under external force.
In order to operate the display module (such as the screen) and/or the apparatus body module of the electronic apparatus in more operation modes and application ranges, a conventional structure as shown in FIG. 1 is disclosed for driving a frame to ascend/descend so as to protect and prevent the keyboard disposed on the apparatus body module from being mis-touched when the display module and/or apparatus body module is rotated.
Referring to FIG. 1, a (dual) rotary shaft B and a case C enclosing the shaft B are mounted on the apparatus body module A1 of an electronic apparatus A. The rotary shaft B has an eccentric section B1, which is eccentrically rotatable with the rotation of the rotary shaft B. A transmission support B2 is connected to the eccentric section B1. The transmission support B2 cooperates with a connection section B3 to assemble with a carrier body B4. When a user operates the display module or the apparatus body module A1 to 180°˜360° rotate/open the same to serve as a tablet, the eccentric section B1 of the rotary shaft pushes the transmission support B2, the connection section B3 and the carrier body B4 to (longitudinally) displace. At this time, the carrier body B4 pushes a frame A2 disposed on the apparatus body module A1 to ascend/descend, whereby the frame A2 is positioned at a height higher than that of the keyboard A3 as a support frame for the electronic apparatus. Also, the frame A2 serves to protect and prevent the keyboard A3 disposed on the apparatus body module A1 from being mis-touched.
In the above structure, in order to permit the transmission support B2 to be drivingly connected to the eccentric section B1 of the rotary shaft, the case C must be formed with notch C1 for the transmission support b2 to pass and move through. Obviously, the notch C1 will affect the appearance design and visual feeling of the electronic apparatus A as a whole. Also, the dust or the like is likely to pass through the notch to accumulate on the components inside the case C. This is not what we expect.
Moreover, with respect to the assembling process and structural design of the transmission device of the rotary shaft, the connection section B3 must be equipped with a claw section B5 for holding the transmission support B2. In addition, an L-shaped restriction board A5 is disposed on a chassis A4 of the apparatus body module A1. The restriction board A5 is assembled with a raised section B6 formed on the connection section B3, whereby the connection section B3 is restricted on the chassis A4 to move along with the transmission support B2. As well known by those who are skilled in this field, the cooperative structure between the transmission support B2, the connection section B3 and the chassis A4 is relatively complicated. This increases the difficulty in assembling the components.
The conventional transmission device of the rotary shaft and the relevant connection components thereof have some shortcomings in use and structural design that need to be overcome. It is therefore tried by the applicant to provide a transmission device applied to rotary shafts to eliminate the shortcomings existing in the conventional transmission device so as to widen the application range of the transmission device. For example, in comparison with the conventional transmission device of rotary shaft, the transmission device of the present invention is applied to a notebook or a small-size electronic apparatus. In condition of lightweight and thin design, the case enclosing the rotary shaft is kept complete to improve the appearance and visual feeling of the electronic apparatus. Also, the case is free from the notch so that the dust or the like will not accumulate on the components arranged in the case. Moreover, the transmission device of the present invention is simplified relative to the complicated cooperative structure of the conventional transmission device. Therefore, the transmission device of the present invention is easy to assemble.